I'll be quite keen to know if anybody had remapped a 5 series before, and how it affected their warranty and performance, including mileage.
It wouldn't be a bad idea if they can enhance the performance by the numbers they have suggested in their website.

Well BMW insurance is voided if you modify the car with a new map or a box for the engine control. Some tuning companies sell additional insurance.

In the EU, the car also becomes illegal because the manufacturer gets an EU wide approval for the car that includes the emission levels. Any tampering with the car and it loses this approval.

If you crash the car and the insurance company finds out about the remap you may get reduced or no compensation at all.

Still many owners do remap their cars. Most after the warranty is gone though.

This is why I didn't re-map my 330d and the same reasoning applies to my forthcoming 535d.
Having said that, I might eventually be tempted by a plug-in tuning box. These work by modifying the fuel pressure and turbo boost signals to the ECU, which then reacts accordingly by increasing both values. They are easily removable and, as far as I understand it, they leave no detectable electronic trace in the ECU; however, I willingly stand to be corrected on the latter point.
Another consideration is that the easy remove option is, of course, dependent on access to the engine bay; a front-end collision could preclude that and I imagine, unless previously declared, you'd then find yourself without insurance.

This is why I didn't re-map my 330d and the same reasoning applies to my forthcoming 535d.
Having said that, I might eventually be tempted by a plug-in tuning box. These work by modifying the fuel pressure and turbo boost signals to the ECU, which then reacts accordingly by increasing both values. They are easily removable and, as far as I understand it, they leave no detectable electronic trace in the ECU; however, I willingly stand to be corrected on the latter point.
Another consideration is that the easy remove option is, of course, dependent on access to the engine bay; a front-end collision could preclude that and I imagine, unless previously declared, you'd then find yourself without insurance.

I have tried a tuning box for on my 120dM and the effect was massive. As far as I am told it leaves traces in the ECU, but I guess this would only be investigated by BMW if you have a warranty claim related to the engine, turbo, clutch, transmission etc.

I had a failure on a control arm for the turbo in my 120dM just after it went of warranty. BMW granted goodwill for most of the repair cost.

Bullshlt or not judge for yourselves. Spoke to a friend of a friend who works as the service head at a BMW dealership about a remap of my 523i.

1. He claims the difference in power between 523i and 528i is pure software.

2. On the E60 a remap would be found out if actively investigated by the dealer or BMW. In the course of a normal service the dealer wouldn't see it.

3. On the F10 if there has been a remap performed once the car is connected to the computers for service the evidence of the remap will show up immediately at the BMW Batman Cave in Munich even if the dealer doesn't see it.

To me no. 3 sounds like a BS rumor spread by BMW to scare people away from tampering with their cars but hey, who knows?

Bullshlt or not judge for yourselves. Spoke to a friend of a friend who works as the service head at a BMW dealership.
On the F10 if there has been a remap performed once the car is connected to the computers for service the evidence of the remap will show up immediately at the BMW Batman Cave in Munich even if the dealer doesn't see it.

With the way of modern technology, this doesn't surprise me in the least and I'm inclined to believe there's an element of truth in the statement.
Yet another reason for me to stay clear of re-maps whilst the warranty's still active. I reckon the sub 6 seconds 0-60 of my forthcoming 535d will be enough to be getting on with for a while

3. On the F10 if there has been a remap performed once the car is connected to the computers for service the evidence of the remap will show up immediately at the BMW Batman Cave in Munich even if the dealer doesn't see it.

What about tuning boxes, how could they tell you are completely bypassing the ECU and there is no evidence once removed?

What about tuning boxes, how could they tell you are completely bypassing the ECU and there is no evidence once removed?

Tuning boxes don't bypass the ECU, they modify the signals going into it, which then makes the ECU increase fuel and turbo boost pressures.
Like 'Gorban', I imagine that these settings will be logged in the memory.

I really don't see how, 4 years on my e90 never had a problem even when I had the system checked over after ems light came on.

I think the answer lies in your comment - "4 years on..." Technology doesn't stand still and a lot has happened in that time.
If you think about it from BMW's pint of view, it's perfectly understandable for them to utilise any software to counter warranty claims resulting from unapproved engine modifications.
Annoying nonetheless, but a sign of the times - 'Big Brother' is well and truly with us.

Has anyone actually cracked the code on the latest version of the N47 (520d, as in the F10/11) engine?

BTW, the connection back to Germany is on the cards, if not already in progress, from what I have read. Read the trade press and the car makers have had enough of engine tuning in warranty periods and are working harder to detect on any connection, at service scope for example.